Abstract

We conducted the geochemical modeling of trace element contents for primary melts of olivine-phyric rocks from Kamchatsky Mys. This modeling reveals substantial chemical heterogeneity of their source while the average source composition is close to the enriched DMM (E-DMM). The average estimation of the melting degree is in the range from 9.1 ± 3.8% for the model of modal batch melting to 15.4 ± 5.2% for the model of accumulated fractional melting, which is slightly higher than the estimation for primitive mid-ocean ridge basalt (MORB) glasses (7.4 ± 2.2% and 12.5 ± 3.8% respectively). It is in a good agreement with high melting degrees estimated earlier for other rocks of the Kamchatsky Mys ophiolites. Low pressure of mantle melting caused by the elevated speed of decompression relative to the average MORB could explain elevated melting degrees estimated for Kamhcatsky Mys ophiolites as well as their characteristic Sr-anomalies and sulfide saturation on the earliest stages of magmatic evolution.

中文翻译：

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Kamchatsky Mys橄榄橄榄岩的来源组成和熔融程度的变化：熔体中微量元素含量的地球化学模拟结果

摘要

我们进行了堪察加半岛Mys橄榄石-天然岩石初熔体中微量元素含量的地球化学模拟。该模型揭示了其来源的大量化学异质性，而平均来源组成接近富集的DMM（E-DMM）。熔融度的平均估计值介于模式批式熔化模型的9.1±3.8％到累积分式熔化模型的15.4±5.2％的范围内，略高于原始中洋脊玄武岩的估计值（MORB）眼镜（分别为7.4±2.2％和12.5±3.8％）。它与坎帕奇Mys蛇绿岩的其他岩石先前估计的高熔融度高度吻合。